docs: def insrtd(item, inset):
      """
      Insert an item into a double precision set.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/insrtd_c.html
  
      :param item: Item to be inserted.
      :type item: Union[float,Iterable[float]]
      :param inset: Insertion set.
      :type inset: spiceypy.utils.support_types.SpiceCell
      """
      assert isinstance(inset, stypes.SpiceCell)
      if hasattr(item, "__iter__"):
          for d in item:
              libspice.insrtd_c(ctypes.c_double(d), ctypes.byref(inset))
      else:
          item = ctypes.c_double(item)
          libspice.insrtd_c(item, ctypes.byref(inset))